JPS597511A - Drilling tool - Google Patents

Abstract

PURPOSE:To manufacture the drilling tool used in soft material easily by rolling. CONSTITUTION:Rolling process is applied to a round bar blank to give thread form thereto. Thread rolling is completed by a single process by rolling with a convergent type die plate having an angle, at which slant faces 10 and 10' at the back of flutes 3 and 3' (or slant faces corresponding with slant faces at the front of ridges 6 and 6') are rendered to be one-half of the point angle A. The leads of the flutes 3 and 3' are made small so as to take a form near to multiple-start thread and the angle between the slant faces 10 and 10' as they are is made coincidence with the point angle and the tip cutting edges are made in a pair of spirals starting from a point 8 on the center line.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the shape of a drilling tool, and its purpose is to provide a tool for use on soft materials such as horseshoe boards, soft metals, and plastics at low cost. The purpose of the present invention is to provide technical KFj, a method for obtaining a shape of a drilling tool that can be easily produced by rolling process, and a tool shape that makes drilling work more effective. It's about getting. Yet another object is to obtain a tool shape that can be used as a tip-drilling part of a self-drilling screw.

The present invention will be described by way of embodiments shown in the accompanying drawings. For convenience, the explanation will be made using drill terminology. In FIG. 1, there is a tool body 2 adjoining and integrally formed with the shank 1. The body 2 of the and is formed by carving two V-shaped grooves 6 and 3' into a round bar material in the form of a helical winding with a certain twist angle. The groove 6.6' has a rounded or flat surface 5.4' of suitable size at its bottom 4.4'. It has a rounded shape.

Mountains 6.6 formed by adjacent V-shaped grooves 6 and 6'
At the top of ', the land width is made small and the margin width is almost linear to form a sharp shape, and two cutting edges 7.7' are formed. Between 3A and 1 winding near the tip 8 of the helical wire, the depth of the groove 6°6' becomes gradually shallower toward the tip, and the spine part (web) at the center of the material gradually becomes shallower. Eventually, both the depth of the grooves 6 and 3' and the core thickness at the tip of the web disappear, and the two cutting edges 7. 7' is configured to match.

The depth of the groove 6.6' is made shallow by the bottom 4.4 of the groove.
This is done by gradually increasing the amount of roundness or flat surface 5.5' toward the tip, and by gradually bringing the top of ridge 696', that is, the cutting edge 7.7', closer to the center line 0-0. , these two cutting edges 7, 7' approach each other in a thin spiral manner, and meet at a point 8 at the tip.

The thinly wound cutting edge 7.7'' at the tip is particularly designated by 9.9' in the figure.

Rear slope 10°10' in V-shaped groove 6°6'
The angle made with the center line 0-0 is half the tip angle A. This is one of the constituent requirements of the present invention.

This point angle A is approximately 1, as in the case of a normal drill.
The standard angle is 20°, but depending on the material of the workpiece, grooves 6 and 3'
It is determined by considering the lead, number of tool grooves, difficulty of rolling process, etc.

The tip angle A in Fig. 1 is approximately 120° with 2 grooves.
The one in Figure 5 has three grooves and an angle of about 815°.

The angle of the peak 6.6' is usually set at around 70° to 80°.
.

It will be done. Furthermore, said angle with the center line 0-0 of the rear slope 10.10' of the grooves 6, 6' remains constant over the entire length of the tool body 2 and is also the same at the tip.

As mentioned earlier, the numbers of the 7-shaped grooves 6, 6 are shown as 2 (Fig. 1) and 3 (Fig. 6) in the embodiment, but may be changed if necessary for the design. You can also choose other numbers.

Cutting edges 7, 7' and a thinly wound cutting edge 9 at the tip.
9' is usually polished after heat treatment and hardened to make it sharp, as is the case with known drills, reamers, etc., but when this tool is used as the tip of a self-drilling screw, Because it only needs to withstand wear, seizure, and breakage once, the polishing process is omitted and the cutting edges 7.7' and 9.9' are formed sharply in the rolling process. It's boring. Furthermore, when using the tool on soft materials such as plastics or wood, it can be used without hardening if the material of the tool is carefully selected.

The present invention is configured as described above, and substantially includes:
The tops of the threads 6, 6' of the multi-thread screw are cutting edges 7, 7', and the tips are thinly wound and concave to a single point. Therefore, it can be said that the shape has a cutting edge 7°7'-9,9', which is a shape in which a stretched thinly wound coil is connected to the tip of a stretched circular coil.

In order to give this shape to the round bar element i, it is desirable to use a thread rolling method. Slope 1o, 1 behind groove 6.6
0' (this coincides with the front slope of mountain 6.6') is set at half the tip angle A, and if rolled using a die plate with a tipped tip, the tip will be rolled. It can be manufactured in one step. This is very effective when producing self-drilling screws with pre-drilled screws.

Attempts to roll a tool of this shape and replace it with a conventional drill as a drilling tool have been fraught with various difficulties, and there is still no tool that can fully meet the demands. It was.

In the tool of the present invention, (1) the lead of the grooves 6, 6 is made smaller than that of a normal drill, giving it a shape similar to a multi-thread screw. (2) Groove 6. ! Slope after 1 10.10'
to match its tip angle. (3) The cutting edge at the tip has a spiral shape that starts from a point 8 on the center line. As a result, we were able to obtain a new shape that is suitable for practical use.

According to experiments, when the tool of the present invention was quenched as it was after rolling, it was possible to drill a through hole in a 6 mm steel plate with a tool with an outer diameter of approximately 15 mm. It seemed that the results were better if the rotation speed was slower.

The tool of the present invention has a small land width, almost a linear width, and a cutting edge of 9.9' at the tip.
As shown in FIGS. 2 and 6, there are a plurality of circular windings starting from a point 8 on the center line 0-0, each rotating approximately 3A to 1 time to form a cutting edge 7 of the same diameter. It is characterized by a gradual and smooth connection to 7'. The fact that the cutting edge 9° at the tip has a shape that matches one point 8 means that
Even if you try to drill holes without punching the workpiece, the center of the tool is not fixed, and the tip of the tool often moves unstablely, as if drawing a map. This has the advantage that when the present invention is used at the tip of a self-drilling screw, the workability is very improved.

In addition, in the tool of the present invention, the cutting edge 9.9' is formed to have a length of 7% to 1 turn of the helical wire wound around the point 8 at the tip. The blade length is longer than that of conventional drills, which are straight, so there is less chattering during operation, and the cutting edge at the tip has a
．． The cutting edge 7.7'lC of the diameter portion of 9 gradually and smoothly connects, which has the effect of reducing the impact at the moment the hole penetrates the workpiece. This means that it is effective not only for drilling holes, but also for use as a reamer, and can be used on the tip of a self-drilling screw to screw in while exposing a small pilot hole that has already been drilled. 0 can also be used for

[Brief explanation of the drawing]

The drawings show an embodiment of the drilling tool of the present invention.
Fig. 1 is a front view of the first embodiment, Fig. 2 is an end view of Fig. 1, Fig. 3 is a longitudinal sectional view of the body taken along the line FIG. 6 is a front view of the second embodiment, and FIG. 6 is an end view of FIG. 6. 100. Shank, 2゜6. Body, 6,6.
. , 7-shaped groove, 4.4', bottom, 5.5. , , rounded or flat surface (at the bottom of the groove), 6.
6',...Mountain, 75 units 00. Cutting edge, 816. One point at the tip, 9, 9',, Cutting edge at the tip, 10,1o
',,, <The slope behind Misonon. Calculation 2 Figure υ 1st Calculation 6 Calculation 5 Figure

Claims (1)

[Claims] In a multi-thread screw type tool that is formed by carving a plurality of continuous V-shaped grooves in a helical pattern on the outer peripheral surface of a round bar material,
As the depth of the groove in the V-shaped groove that makes instant contact is gradually made shallower, the spine (web) at the center of the tool is also gradually made smaller, and eventually the depth and core thickness of the groove become smaller. By eliminating the above, the tips of the plurality of cutting edges are made to approach each other in a thin spiral shape, so that they meet at one point on the center line, and furthermore, on the slope at the rear of the V-shaped groove, A drilling tool characterized by having an angle that is half the tip angle of the tool.